Die rolling



May 31, 1932. COYLE 1,860,608

P. L. COY

May 31, 1932.

2 Sheets-Sheet 2 Patented May 31, 1932 UNITED STATES ASSIGNOR T0 REPUBLIC STEEL COR- A CORPORATION OF NEW JERSEY DIE ROLLING Application filed November 20, 1929. Serial No. 408,437.

My invention relates to the production of formed metal articles by die rolling and, particularly, to a method and apparatus for maintaining the desired length of the article after the die rolls have been reduced in diameter as aresult of redressing, as well as for changing the length of the finished article if this should be found desirable.

In my prior Patent No. 1,597,955, I have pointed out that die rolls become worn after considerable use and must be redressed in order to turn out a perfect product. In said patent, I disclosed a method of maintaining the desired length of the rolled article even though the length of the matrix or forming groove in the roll is perceptibly decreased by the reduction in roll diameter effected by the extra thickness of redressing operation. This method is satisfactory for the first few redressings given to the rolls. Even after they have been redressed several times, they may be continued in service by the use of the present invention.

It is also desirable to be able to vary the finished length of a rolled article to compensate forslight design or other changes.

I have invented an improved method of accomplishing these objects and, according to the improved method, I provide flash gutters in the die rolls on each side of the forming grooves. The purpose of the flash gutters is to provide a supply of metal from which can be drawn the material necessary to produce an added extrusion of the rolled article after the rolls have been redresscd several times and considerably reduced in diameter, or when it is desired to increase the finished length of the article.

The redressing operation is carried out as explained in my patent referred to above. The flash gutters are not restored to their original depth during the redressing operation but are left reduced in depth by the reduction in the diameter of the rolls during redressing. The reduction. in the depth of thc flash gutters causes the flash formed on the rolled article, after the rolls have been redressed, to be thinner than that formed by the rolls in their .original. condition. The metal which otherwise would have formed the flash is extruded in the body of the rolled article and thus adds to its length to compensate for the reduction in the length of the matrix groove which results from the reduction in the diameter of the roll and the resinking of the groove.

To vary the finished length of a rolled article, I increase the depth of the flash gutters to shorten the article. To increase its length, I weld metal in the butters and recut them to a depth less than they had originally. This variation in the depth of the gutter changes the distribution of metal between the flash and the body of the article so that the metal which previously formed the flash now forms the body of the article, in the ease of a reduction in the depth of the flash gutters.

For a complete understanding of my in vention, reference is made to the accompanying drawings illustrating a present preferred embodiment thereof. In the drawings,

Figure 1 is a partial sectional view taken in a plane perpendicular to the axes of the rolls through the axis of the roll matrices;

Figure 2 is a partial section taken on a, plane including the axes of the rolls;

Figure 3 is a view similar to Figure 2 showing the rolls after redressing;

Figure 4 is a plan view of a rear axle shaft for motoncars as produced by a known process of die rolling; and

Figures 5, 6 and 7 are sectional views along the line XX of Figure 4, showing the variations in the dimensions of the flash which cause the length of the finished article to vary. 7

Referring to the drawings and, particularly, to Figures 1 and 2,'the invention is adapted for use in connection with die rolls such as those partially illustrated at 10 and 11. The rolls 10 and 11 have corresponding matrix grooves 12 and 13 which are adapted to form a heated leader when the latter is fed through the rolls. The excess metal contained in the leader over that necessary for the formation of the various portions of the completed article, is disposed of in flash which is formed in flash gutters 14 and 15 adjacent the matrix grooves 12 and 13.

The art of die rolling articles with flash formed integrally therewith is now welling the excess metal.

' original condition.

known and I have improved upon well known processes by providing specially formed gutters adjacent the matrix grooves for receiv- As shown in Figure 2, the flash gutters 14 and 15 are of gradually increasing depth. The gutters do not ex tend to the edges 16 of the matrix grooves but are cut into the'rolls beginning at a point 1 17 some distance from the edge of the grooves. From this point the depth of the flash gutter. increases to amaximum at the point 18 where it meets the gutter adjacent the next matrix groove. I The redressing of flash guttered rolls is accomplished by the method described in my patent referred to above. According to this process, the roll surface is turned down to a depth of from to T g .In order to maintain the proper shape of the rolled article, it is necessary to resink the matrix grooves to their original depth. The reduction in the diameter of the rolls and the resinking of the matrix grooves causes the 'pe-- ripheral length of the matrices to be slightly decreased. After a number of redressings, this decrease in the peripheral length of the matrices is suflicient to produce a shorter article than that turned out by the rolls in their The reduction in the diameter of the rolls, however, causes a corresponding reduction in the depth of the flash gutters 14 and 15. These flash gutters are not sunk to their original depth as are the 7 matrix grooves, but remain of the depth to which they are reduced by the redressing operation, as clearly shown in Figure 3.

Since the roll set remains the same regardless of whether the rolls are new or redressed, the decrease in the depth of the flash gutters causes a corresponding decrease in the thickness of the flash formed on the rolled article. The excess metal which forms the thick flash when the gutters are of their original depth, is extruded into the body of the rolled article when the gutters have been reduced in depth by the redressing operation. This add ed extrusion of thc'rolled article increases the finished length of the latter slightly and so compensates for the slight reduction in the peripheral length of the matrix grooves which is caused by repeated redressing of the rolls and sinking of the grooves.

Figure 4 illustrates a rear axle shaft 19 for motor cars which is produced by die rolling between rolls having flash gutters inaccordance with my invention. which form the flash-' shown at 20.

In addition to compensating for the decrease in the length of the matrix groove, the depth of a flash gutter may be'varied to'cause an increase or decrease in the length of the rolled article whenever desired. whether be-' cause of repeated redressing of the rolls or changes in the design of the rolled article.v If it is desired to decrease the length of the finished product, the flash gutters may be cut deeper. If the length is to be increased, metal is welded in the gutters and the latter are then reworked to a depth less than that of the original gutters. As previously explained, the distribution of the metal between the flash and the finished article determines the length of the latter.

Figure 5 shows the size of the flash produced by new rolls having flash gutters of normal depth as shown in Figure 2. Figure 6 shows the size of the flash produced by rolls the gutters of which have been cut deeper to shorten the length of the rolled article. Figure 7 shows the appearance of flash produced by rolls which have been redressed as in Figure 3. The same type of flash would result from welding-metal into the original grooves and recutting them to a depth less than they originally had. By using the flash gutters herein described, it is possible to produce rolled articles of exact dimensions even after the rolls have been redressed several times. It is also possible to control the length of the finished article by varying the depth of the flash gutters. I I have found it necessary to use flash gutters in accordance with the foregoing descrip tion only where the percentage of reduction in area'affected by the die rolls may be as high as -85%. The section of the axle shaft 19 at the line X-X is of such area, compared to the cross section of the leader, that the flash gutters are necessary to compensate for decrease in the length of the matrix groove on redressing.

The advantages resulting from the invention described include the fact that the rolls may be redressed a greater number of times than has been previously the practice. In spiteof continued redressing the dimensions of the rolled article may be maintained within the required limits and a satisfactory productmanufact-ured. The depth of the flash gutters maybe made such that the rolls ma be redressed a large number of times. In a dition, a. considerable control of the length of the rolled article can be effected by variations in the depth of the flash gutters.

The further steps in the manufacture of:

articles by known die-rolling processes are utilized in'conne'ction with the present-invention but since these are well known, a description thereof is omitted.

Although I have illustrated and described only a single present preferred embodiment of my invention, I do not intend to, be limitedv to the specific terms thereof, sincetheinven- I tion may be otherwise ing from the spirit thereof.

Iclaim: v y 1. The method of renewing die rolls having flash gutters which includes the steps of dressing the roll surface, sinking the die imp iced withiitithg. 5 scope of the following claims ressions therein to maintain the proper epth of the latter, and leaving the flash 511 ters of the depth to which they are reduce by the dressing of the surface, whereby t0 compensate the length of the rolledarticle for the decrease in the peripheral length oi the forming groove resulting from sinking it into the dressed roll.

2. The method of compensating for the decrease in the peripheral length of a forming groove in a die roll having flash gutters, resulting from reductions in the diameter of the roll in redressing it, which includes the step of reducing the depth of the flash gutters as 5 the diameter of the roll is reduced.

3. The method of renewing die rolls having forming grooves and flash gutters which includes the steps of removing the worn surface of the rolls and restoring the forming o grooves only, to their original depth, whereby the reduced depth of the gutters causes an increased extrusion efl'ect to compensate for the'reduction in the length of the grooves.

' In testimony whereof I have hereunto set a fmy hand.

PAUL L. COYLE. 

